After a great deal of futile endeavour, chance at last favoured me.

On the 5th of September one of my guests, fecundated on the 29th of August, began to make her preparations under my eyes, at four o'clock in the afternoon.
One remark before proceeding: all the nests I have obtained in the laboratory--and I have obtained a good number--have without exception been built upon the wire gauze of the covers.

I have been careful to provide the insects with roughened stones and tufts of thyme, both being very commonly used as foundations in the open fields.

The captives have always preferred the network of wire gauze, which affords a perfectly firm foundation, as the soft material of the nest becomes incrusted upon the meshes as it hardens.
In natural conditions the nests are never in any way sheltered; they support the inclemencies of winter, resist rain, wind, frost, and snow, without becoming detached.

It is true that the female always selects an uneven support on which the foundations of the nest can be shaped, thus obtaining a firm hold.